idle used to be steady as a rock until about 1 month ago when i started parking it inside because of cold.... i know that's not the reason for the bad idle, but it's the only thing i've done differently....

50% of time....after warm-up car almost stall rises to 500, drops to about 250, then rises to 1000 then repeats about 10-15 times then stalls.... if i turn a/c on the whole process jumps to about 2000 then slowly returns till it stalls again....

other 50% idle oscillates between 250-1000... with a/c on it jumps to 1500 for a few sec then goes back to oscillating....with p/s when i turn the wheel at stop the idle drops until i quit turning the wheel

what valves or electrical equip. could be clogged?? malfunctioning??

checked tps, timing.... both are ok...

thanks, paul

 

BAC valve. Or other vacuum leak.

 

I'd like to guess at the bac also. Plus I think/guess your idle has not been set properly. The bac is trying to make up for an incorrect idle seting. The idle needs to be set with the initial set coupler installed. Set at or as close to 750 as possible. The bac main purpose in life is to maintain a 750 idle. If it sees a low idle it'll por more air til the idle rises to or above 750. If the speed rises over that the bac duty cycle will drop down.........so now the idle speed once more drops down because the bac isn't feeding as much air and the revs drop waaay down where the incorrect idle was set and the cycle starts all over again...up/down, up down.

I'm betting if you warmed that engine up and then installed the initial set coupler the car would either die or idle waaay down there below 750.

I may not have stated the above exactly as it should have been stated, but the gist is that the idle is set too low with the initial set coupler (on your car) and that is your problem.

Then again, it would be interesting to see if your thermowax is releasing as it should now that the weather is colder. That would hold the throttle plates open a bit more than they are supposed to be open, which would cause idle problems.

Heck. Ignore the above. Get the FSM out and open the Fuel section and check out the thermowax, idle, timing , bac for yourself. You'll find the problem.

 

thanks guys.... what's the initial set coupler??